Estrus Manipulation and Artificial Insemination

Question 1

What is estrus duration for cows

Answer 1

6-30hrs (average 18hrs)

Question 2

Reasons for estrus manipulation

Answer 2

1. Synchronize
2. Initiate cylclicity in anestrous animals
3. Out of season breeding in seasonal species
4. Correct reproductive problem

Question 3

What does PGF2alpha do

Answer 3

Induce luteolysis

Question 4

When is corpus luteum responsive after PGF2alpha in cattle

Answer 4

6-7 days

Question 5

What estrus manipulation drug promotes release of FSH and LH

Answer 5

GnRH analogs-gonadorelin, deslorelin

Question 6

What drugs replicate LH surge

Answer 6

LH analogs- hCG

Question 7

What drug is required for out of season breeding if only using drugs for manipulation

Answer 7

FSH analogs-eCG

Question 8

What hormone is responsible for maintaining pregnancy and blocks LH surge

Answer 8

Progesterone

Question 9

What species is cystorelin approved for

Answer 9

Dairy cattle only

Question 10

What species is lutalyse approved for

Answer 10

Cattle, swine, mares

Question 11

What species is estrumate approved for

Answer 11

Cattle

Question 12

Use of ___in food animals is prohibited for estrus manipulation

Answer 12

Estradiol

Question 13

What are the objectives of synch protocols in cattle

Answer 13

1. Hormonally control the onset of new follicular wave
2. Control the lifespan of both natural and induced CL’s
3. Control time of ovulation for dominant follicle

Question 14

What is the protocol for ovsynch

Answer 14

1. Day zero: GnRH- ovulation of dominant follicle
2. Day 7: PGF2alpha-luteolysis of CL
3. Day 9: GnRH- ovulation of new dominant follicle
4. 24-32hrs later TAI

Question 15

Ovsynch doesn’t work well in heifers only __-__% synch rate, but in mature cows synch rate ___-___%

Answer 15

50-60%, 70-90%

Question 16

What is the protocol for pre synch

Answer 16

Giving 2 injections of PGF2alpha prior to ovsynch to ensure majority of cows will be between 5-12 days of cycle

Question 17

What is major shortcoming of ovsynch

Answer 17

Cattle between 14-15 days of their cycle will not respond to 1st GnRH injection (~10%)

Question 18

Select synch works well with ___not ___

Answer 18

Mature beef cows, heifers

Question 19

What is protocol for select synch

Answer 19

1. Day zero: GnRH injection
2. Day 7: PGF2alpha injection
3. Day 6-13: watch for heat BID and AI 12hrs later
4. Day 13: turn in clean up bulls

Question 20

What is the least predictable step in embryo production and transfer

Answer 20

Super ovulation

Question 21

Semen straws must be ___ and loaded into the AI gun

Answer 21

Thawed

Question 22

Once semen straws are thawed cut the tip of the straw and load with Cotten end facing ___

Answer 22

Away from end of AI gun